FIELD OF THE INVENTION
[0001] The present invention relates to a multi-purpose mortar or cement composition for
(i) inhibiting the corrosion of steel in mortar or cement structures, (ii) repairing,
filling and/or spraying damages, cracks, flaws and cavities in mortar or cement structures
and/or (iii) surfacing, coating and/or protecting mortar or concrete surfaces.
BACKGROUND
[0002] Concrete reparation is a strongly regulated activity. There are many standards to
meet, which impose high product performance level.
[0003] Repairing damaged concrete often requires a system of mortars. The user typically
has to use several products to carry out the reparation works. The system may optionally
comprise a bonding primer, reinforcement corrosion protection, re-profiling mortar
and levelling / smoothing layer. These are commonly 3 or 4 different types of products,
which has the disadvantages of being costly and requiring additional packaging and
storage space.
[0004] Very few multi-purpose mortars exist on the market. None of them have all three following
functions in one single product:
- restoring and preserving passivity of steel bars
- concrete reparation
- concrete surfacing and protection.
[0005] That is because combining all three properties into a single product presents a great
technical challenge, in part because a product approved for each application/function
must meet different standards.
[0006] In fact, to our knowledge, the only multi-purpose mortar product currently commercially
available is Planitop Smooth & Repair from the company MAPEI®. This product, however,
only fulfills two functions: concrete reparation and concrete surfacing.
[0007] In Europe, a mortar suitable for all three above-properties/uses should fulfill the
three following standards: EN 1504-7, EN 1504-2 and EN 1504-3/R2 class.
[0008] One major hurdle for succeeding in designing such a product has to do with the capacity
to obtain the right technical compromise between the three different uses/ purposes.
[0009] First, optimization of the formulation to attain the right granulometry is problematic.
On the one hand, the particle size has to be fine enough for the product to be applied
in very thin layers (surfacing application). On the other hand, fine granulometry
can sharpen shrinkage and entail the appearance of cracks once the mortar applied
in thicker layers (reparation application).
[0010] In addition, designing a mortar that has the desired anti-corrosion properties, and
meets the stringent standard EN 1504-7 is a very difficult challenge. This European
standard is more geared towards paint products, which generally have a different and
more adapted viscosity and consistency than mortars to fulfill standardized requirements.
[0011] Furthermore, to control the shrinkage of the product for each of the three applications/uses
is far from being an easy task. Each version of the product (i.e., anti-corrosion,
reparation, and surfacing) implies the presence of different amounts of water (to
reach the proper viscosity and consistency suitable for each application), which inevitably
leads to different shrinkage behaviours.
[0012] Accordingly, there remains a great need/challenge to develop mortar or cement compositions
that fulfils all three properties into a single product: anti-corrosion, reparation,
and surfacing.
DESCRIPTION
[0013] The present invention provides a solution to this problem by providing in one aspect
a multi-purpose mortar or cement composition for (i) inhibiting the corrosion of steel
in mortar or cement structures, (ii) repairing, filling and/or spraying damages, cracks,
flaws and cavities in mortar or cement structures and/or (iii) surfacing, coating
and/or protecting mortar or concrete surfaces.
[0014] As stated above, optimization of a mortar or cement formulation to attain the right
granulometry is problematic: fine granulometry can sharpen shrinkage and entail the
appearance of cracks once the mortar applied in thicker layers (reparation application).
As the introduction of bigger particles is not possible in the case of the invention,
the only way to prevent the formation of cracks is to find the right combination of
specific anti-shrinkage agents and to adjust as far as possible the reactivity of
the binders.
[0015] In addition, each kind of "properties" (anti-corrosion, reparation and surfacing)
requiring specific pot-life and hardened properties to fit with applicator's requirements,
binders has to be selected according to their reactivity and the composition of the
mortar adjusted to answer customers' needs for each purpose. As a consequence, the
selection of the right additives is a technical challenge as their solubility and
granulometry can have a big influence on the properties at fresh and hardened states
of the cementitious composition.
[0016] Advantageously, the multi-purpose mortar or cement composition comprises:
at least one cementitious binder
at least one filler and sands
at least one antifoam agent
at least one fibre component
at least one anti-corrosion agent
at least one plasticizer or superplasticizer
at least one accelerator
at least one anti-shrinkage agent
and at least one polymer, redispersable polymer or co-polymer.
[0017] Advantageously, the multi-purpose mortar or cement composition comprises (% by weight,
calculated on the total weight of the composition):
15 to 40 % of at least one cementitious binder
50 to 80 % of at least one filler and sands
0.05 to 1.5 % of at least one antifoam agent
0.05 to 1.2 % of at least one fibre component
0.05 to 3.2 % of at least one anti-corrosion agent
0.05 to 1.2 % of at least one plasticizer or superplasticizer
0.1 to 3.5 % of at least one accelerator
0.1 to 4.2 % of at least one anti-shrinkage agent
0.1 to 3,5 % of at least one polymer, redispersable polymer or co-polymer,
wherein the sum of the weight % of the aforementioned components is 100%.
[0018] In the present document, substance names beginning with "poly", such as, for example,
polyglycol, polyethylene, polyvinyl alcohol, polyol, polycarboxylated ether, polyvinyl
acetate or polyvinyl ester, designate substances which formally contain, per molecule,
two or more of the functional groups occurring in their name.
[0019] In the present document, the term "polymer" encompasses firstly a group of chemically
uniform macromolecules which however differ with respect to the degree of polymerization,
molar mass and chain length, which group was prepared by a polyreaction (polymerization,
polyaddition, polycondensation). Secondly, the term also encompasses derivatives of
such a group of macromolecules from polyreactions, i.e. compounds which were obtained
by reactions, such as, for example, additions or substitutions, of functional groups
on specified macromolecules and which may be chemically uniform or chemically nonuniform.
Furthermore, the term also encompasses so-called prepolymers, i.e. reactive oligomeric
preadducts whose functional groups are involved in the synthesis of macromolecules.
[0020] In the present document, the term "polyol" encompasses any desired polymer according
to the above definition which has more than one hydroxyl group.
[0021] The term "pot life" is understood as meaning the duration of processability of reactive
compositions after their mixing with water. The end of the pot life is in most cases
associated with a viscosity increase of the composition such that expedient processing
of the composition is no longer possible.
[0022] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one cementitious binder. The cementitious binder may be selected
from a Portland cement (such as CEM I, II, III, IV or V, according to EN 197-1), a
calcium aluminate cement (CAC) (such as CAC according to EN 14647 type TERNAL® RG
or FONDU® from KERNEOS), a sulfo aluminate cement, a gypsum-based binder, lime, hydrated
lime, silica fume, or a mixture thereof. Advantageously, the cementitious binder represents
15 to 40 % by weight, calculated on the total weight of the composition. For example,
the cementitious binder represents 25.75 % ± 10% by weight, calculated on the total
weight of the composition.
[0023] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one filler and sands. The filler and sands may be selected among
siliceous sands or fillers having a sieve curve between 0.05mm and 1.5mm, calcareous
filler (such as OMYACOAT 850-OG or OMYACOAT BL 200 from OMYA), precipitated ultra
fine calcium carbonate (such as SOCAL 31 from SOLVAY), or a mixture thereof. Advantageously,
the filler and sands may represent 50 to 80 % by weight, calculated on the total weight
of the composition. For example, the filler and sands may represent 67.80 % ± 10%
by weight, calculated on the total weight of the composition. Typically, a filler,
as used herein, refers to a filler which ranges below 100 □m in particle size, while
filler having a particle size greater than 100 □m is referred to as a sand.
[0024] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one antifoam agent. The antifoam agent may be selected from a polyglycol,
ethoxylate fatty alcohol, polisiloxane, or a mixture thereof [for example, LUMITEN*
EP 3108 from BASF, AGITAN P813 from MUNZIG, AXILAT™ DF 6352 DD from MOMENTIVE may
be used]. Advantageously, the antifoam agent may represent 0.05 to 1.5 % by weight,
calculated on the total weight of the composition. For example, the antifoam agent
may represent 0.10 % ± 1% by weight, calculated on the total weight of the composition.
[0025] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one fibre component. The fibre component may be selected from a
polyolefines fibres (such as polyethylene or poplypropylene), nitryl, polyvinyl alcohol
(PVA), glass with or without anti-alkaline protection, cellulose, flax or hemp fibre
component, or a mixture thereof [For example, SIKACRACKSTOP® 6 or 12mm from SIKA,
KURALON RF 1000 from KURARAY, FIBRAFLEX from SAINT-GOBAIN, CEM-FIL® ANTI-CRACK™ HP
from SAINT-GOBAIN, ARBOCEL® from JRS, FIBREMESH® from FIBREMESH® may be used]. Advantageously,
the fibre component may represent 0.05 to 1.2 % by weight, calculated on the total
weight of the composition. For example, the fibre component may represent 0.20 % ±
1 % by weight, calculated on the total weight of the composition.
[0026] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one anti-corrosion agent. The anti-corrosion agent may be selected
from a sodium nitrite, calcium nitrite, dicyclohexylamine nitrite, mono-ethanolamine
benzoate, ethanolamine benzoate, ethanolamine, diethanolamine, N.N-dimethylethanolamine,
TRIS(hydroxymethyl-aminomethan), or a mixture thereof [For example, NITRITE DE SODIUM
RW from BASF purity ≥ 98.7%, MONOETHANOLAMINE BENZOATE < 100µm from BRENNTAG may be
used]. Advantageously, the anti-corrosion agent may represent 0.05 to 3.2 % by weight,
calculated on the total weight of the composition. For example, the anti-corrosion
agent may represent 1,05 % ± 2% by weight, calculated on the total weight of the composition.
[0027] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one plasticizer or superplasticizer. The plasticizer or superplasticizer
may be selected from a polycarboxylated ether (PCE), lignosulfonate, melamine formaldehyde,
or a mixture thereof [For example, SIKA®VISCOCRETE® from SIKA, FLUBE CA 140 from GIOVANNI
BOZZETTO SpA, PERAMIN® COMPAC from KERNEOS may be used] Advantageously, the plasticizer
or superplasticizer may represent 0.05 to 1.2 % by weight, calculated on the total
weight of the composition. For example, the plasticizer or superplasticizer may represent
0.05 % ± 1 % by weight, calculated on the total weight of the composition.
[0028] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one accelerator. The accelerator may be selected from a calcium
formate, aluminium oxide, chlorinated or unclorinated accelerator, lithium salts (such
as lithium carbonate), nitrite salts (such as sodium nitrite), nitrate salts (such
as calcium nitrate), or a mixture thereof [For example, CALCIUM FORMATE from LANXESS
- granulometry < 0.5mm-purity : 97.5% -, PROX-MAT C-143 from SYNTHRON, SODIUM CARBONATE
from BRENNTAG, GELOXAL® 10 from Industrias Quimicas del Ebro may be used]. Advantageously,
the accelerator may represent 0.1 to 3.5 % by weight, calculated on the total weight
of the composition. For example, the accelerator may represent 1.50 % ± 2% by weight,
calculated on the total weight of the composition.
[0029] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one anti-shrinkage agent. The anti-shrinkage agent may be selected
from powder products or flakes, such as a polyol (SITREN® PSR100 from EVONIK), coated
lime, a crystalline expansive agent (such as DENKA CSA from NEUCHEM SRL), aluminium
powder, azodicarbonamide, or a mixture thereof [For example, DISPELAIR P430 from BLACKBURN
CHEMICALS limited, UNIFOAM AZ STD et/ou ULTRA, PERAMIN SRA 40 from KERNEOS, BLITZ
EXPANDAL from BENDA-LUTZ WERKE GmbH, EXPAN K from MITSUI & CO may be used]. Advantageously,
the anti-shrinkage agent may represent 0.1 to 4.2 % by weight, calculated on the total
weight of the composition. For example, the anti-shrinkage agent may represent 2.035
% ± 2% by weight, calculated on the total weight of the composition.
[0030] Advantageously, the multi-purpose mortar or cement composition according to the invention
comprises at least one polymer, redispersable polymer or co-polymer. The polymer,
redispersable polymer or co-polymer may be selected from polyvinyl acetate, polyvinyl
ester including polyvinyl acetate silane terminated polymer and polyvinyl ester silane
terminated polymer, or a mixture thereof [For example, ELOTEX FL 1210 from SAINT-GOBAIN,
ELOTEX MP 2100 from SAINT-GOBAIN, AXILAT HP 8510 from MOMENTIVE, AXILAT UP600B from
MOMENTIVE, VINNAPAS 8031 H from WACKER - Tg comprised between 0°C to 16°C and TMMF
between 0 and 8°C, may be used]. Advantageously, the polymer, redispersable polymer
or co-polymer may represent 0.1 to 3,5 % by weight, calculated on the total weight
of the composition. For example, the polymer, redispersable polymer or co-polymer
may represent 1.5 % ± 2% by weight, calculated on the total weight of the composition.
[0031] Optionally, the multi-purpose mortar or cement composition according to the invention
may comprise at least one chromium reducer. The chromium reducer may be CHROMATEX
C®, which may be purchased from the company TRICOSAL CHEMIE or CEM PROTECTOR SN 100
from MIG. Advantageously, the chromium reducer may represent 0.01 to 0.1.% by weight,
calculated on the total weight of the composition. For example, the chromium reducer
may represent 0.02 % ± 0.05% by weight, calculated on the total weight of the composition.
[0032] Advantageously, the multi-purpose mortar or cement composition according to the invention
may comprise:
25.75 % ± 10% of at least one cementitious binder
67.80 % ± 10% of at least one filler and sands
0.10 % ± 1% of at least one antifoam agent
0.20 % ± 1 % of at least one fibre component
1,05 % ± 2% of at least one anti-corrosion agent
0.05 % ± 1 % of at least one plasticizer or superplasticizer
1.50 % ± 2% of at least one accelerator
2.035 % ± 2% of at least one anti-shrinkage agent
1.5 % ± 2% of at least one polymer, redispersable polymer or co-polymer,
wherein the sum of the weight % of the aforementioned components is 100%.
[0033] Advantageously, the multi-purpose mortar or cement composition according to the invention
may comprise:
25.75 % ± 10% of at least one cementitious binder
67.80 % ± 10% of at least one filler and sands
0.05-1.10% of at least one antifoam agent
0.05-1.20% of at least one fibre component
0.05-3.05% of at least one anti-corrosion agent
0.05-1.05% of at least one plasticizer or superplasticizer
0.1-3.50% of at least one accelerator
0.1-4.035% of at least one anti-shrinkage agent
0.1-3.5% of at least one polymer or co-polymer,
wherein the sum of the weight % of the aforementioned components is 100%.
[0034] Optionally, the multi-purpose mortar or cement composition according to the invention
may additionally comprise 0.02% ± 0.05% of chromium reducer, wherein the sum of the
weight % of the aforementioned components is 100%.
[0035] The multi-purpose mortar or cement composition according to the invention may further
comprise conventional admixtures like air entraining admixtures, defoamers, retarders,
set accelerators, hardening accelerators, hydrophobising or shrinkage reducing admixtures.
[0036] The multi-purpose mortar or cement composition according to the invention may be
prepared by mixing and blending together all the components according to conventional
methods.
[0037] In another aspect, there is provided a wet mortar or cement composition, comprising
a multi-purpose mortar or cement composition according to any one of the previous
embodiments and 13.60 to 20.40 % by weight of water relative to the weight of the
multi-purpose mortar or cement composition, depending on the intended use of the wet
composition (i.e., anti-corrosion, repair, or resurfacing).
Anti-corrosion mortar or cement composition
[0038] In another aspect, there is provided an anti-corrosion mortar or cement composition
for inhibiting the corrosion of steel in mortar or cement structures, comprising a
multi-purpose mortar or cement composition according to any one of the previous embodiments
and 18.40 to 20.40 % by weight of water relative to the weight of the multi-purpose
mortar or cement composition.
[0039] Such anti-corrosion mortar or cement composition may be readily and simply prepared
by adding a suitable amount of water to a multi-purpose mortar or cement composition
according to any one of the previous embodiments.
[0040] Accordingly, there is provided a process for preparing an anti-corrosion mortar or
cement composition for inhibiting the corrosion of steel in mortar or cement structures,
comprising a step of mixing a multi-purpose mortar or cement composition according
to any one of the previous embodiments with 18.40 to 20.40 % by weight of water based
on the weight of the multi-purpose mortar or cement composition.
[0041] In yet another aspect, there is also provided a method for inhibiting the corrosion
of steel in mortar or cement structures, the method comprising applying an anti-corrosion
mortar or cement composition according to any one of the preceding embodiments to
a steel piece of the mortar or cement structure.
[0042] There is also provided a method for inhibiting the corrosion of steel in mortar or
cement structures, the method comprising:
- a) providing an anti-corrosion mortar or cement composition comprising a multi-purpose
mortar or cement composition according to any one of the preceding embodiments and
18,40 to 20,40 % by weight of water relative to the weight of the multi-purpose mortar
or cement composition; and
- b) applying the anti-corrosion mortar or cement composition obtained in step a) to
a steel piece of the structure.
[0043] The anti-corrosion mortar or cement composition, once applied, may be allowed to
set and dry, in particular prior to applying any other products.
[0044] The water content allows the anti-corrosion mortar or cement composition to reach
the consistency of a paint. It can therefore be applied to steel pieces in mortar
or cement structures with a brush or paint-brush.
[0045] The water content may range between 18.40 to 20.40 %, preferably 18.50 to 20.00 %,
more preferably about 19 % by weight of water based on the weight of the multi-purpose
mortar or cement composition.
[0046] The anti-corrosion mortar or cement composition may be applied with a thickness ranging
from 1 to 6 mm, preferably 1 to 4 mm, most preferably 1 to 2 mm.
Repair mortar or cement composition
[0047] In another aspect, there is provided a repair mortar or cement composition for repairing,
filling and/or spraying damages, cracks, flaws and cavities in mortar or cement structures,
comprising a composition according to any one of the previous embodiments and 13.60
to 16.00 % by weight of water relative to the weight of the multi-purpose mortar or
cement composition.
[0048] Such repair mortar or cement composition may be readily and simply prepared by adding
a suitable amount of water to a multi-purpose mortar or cement composition according
to any one of the previous embodiments.
[0049] Accordingly, there is provided a process for preparing a repair mortar or cement
composition for repairing, filling and/or spraying damages, cracks, flaws and cavities
in mortar or cement structures, comprising a step of mixing a composition according
to any one of the previous embodiments with 13.60 to 16.00 % by weight of water based
on the weight of the multi-purpose mortar or cement composition.
[0050] In yet another aspect, there is also provided a method for repairing, filling and/or
spraying damages, cracks, flaws and cavities in mortar or cement structures, the method
comprising applying a repair mortar or cement composition according to any one of
the preceding embodiments to a damaged concrete structure. The repair mortar or cement
composition, once applied, may be allowed to set and dry, in particular prior to applying
any other products.
[0051] There is also provided a method for repairing, filling and/or spraying damages, cracks,
flaws and cavities in damaged mortar or cement structures, the method comprising:
- a) providing a repair mortar or cement composition comprising a multi-purpose composition
according to any one of the preceding embodiments and 13,60 to 16,00 % by weight of
water relative to the weight of the multi-purpose mortar or cement composition; and
- b) applying the repair mortar or cement composition obtained in step a) to the damaged
concrete structure.
[0052] The water content allows the repair mortar or cement composition to reach the desired
consistency enabling its application for repairing, filling and/or spraying damages,
cracks, flaws and cavities in mortar or cement structures.
[0053] The water content may range between 13,60 to 16,00 %, preferably 14,00 to 16,00 %,
more preferably about 15 % by weight of water based on the weight of the multi-purpose
mortar or cement composition.
[0054] The repair mortar or cement composition can be applied manually or mechanically,
with conventional trowel means or suitable machine application such as a wet spray
machine.
[0055] The repair mortar or cement composition may be applied with a thickness ranging from
2 to 40 mm, preferably 2 to 35 mm, most preferably 2 to 30 mm.
Resurfacing mortar or cement composition
[0056] In another aspect, there is provided a resurfacing mortar or cement composition for
surfacing, coating and/or protecting mortar or concrete surfaces, comprising a multi-purpose
mortar or cement composition according to any one of the previous embodiments and
16.40 to 18.40 % by weight of water relative to the weight of the multi-purpose mortar
or cement composition.
[0057] Such resurfacing mortar or cement composition may be readily and simply prepared
by adding a suitable amount of water to a multi-purpose mortar or cement composition
according to any one of the previous embodiments.
[0058] Accordingly, there is provided a process for preparing a resurfacing mortar or cement
composition for surfacing, coating and/or protecting mortar or concrete surfaces,
comprising a step of mixing a multi-purpose mortar or cement composition according
to any one of the previous embodiments with 16.40 to 18.40 % by weight of water based
on the weight of the multi-purpose mortar or cement composition.
[0059] In yet another aspect, there is also provided a method for surfacing, coating and/or
protecting mortar or concrete surfaces, the method comprising applying a resurfacing
mortar or cement composition according to any one of the preceding embodiments. The
resurfacing mortar or cement composition, once applied, may be allowed to set and
dry, in particular prior to applying any other products.
[0060] There is also provided a method for surfacing, coating and/or protecting mortar or
concrete surfaces, the method comprising:
- a) providing a surfacing mortar or cement composition comprising a multi-purpose mortar
or cement composition according to any one of the preceding embodiments and 16,40
to 18,40 % by weight of water relative to the weight of the multi-purpose mortar or
cement composition; and
- b) applying the surfacing mortar or cement composition obtained in step a) to the
mortar or concrete surface.
[0061] The water content allows the resurfacing mortar or cement composition to reach the
desired consistency enabling its application for surfacing, coating and/or protecting
mortar or concrete surfaces.
[0062] The water content may range between 16,40 to 18,40 %, preferably 16,50 to 18,00 %,
more preferably about 17 % by weight of water based on the weight of the multi-purpose
mortar or cement composition.
[0063] The resurfacing mortar or cement composition may be applied manually or mechanically,
with conventional trowel means or suitable machine application such as a wet spray
machine.
[0064] The resurfacing mortar or cement composition may be applied with a thickness ranging
from 2 to 10 mm, preferably 2 to 6 mm, most preferably 2 to 4 mm.
[0065] In yet another aspect, there is provided a use of a composition of a multi-purpose
mortar or cement composition according to any one of the preceding embodiments for
(i) inhibiting the corrosion of steel in mortar or cement structures, (ii) repairing,
filling and/or spraying damages, cracks, flaws and cavities in mortar or cement structures
and/or (iii) surfacing, coating and/or protecting mortar or concrete surfaces. The
various embodiments described herein for the (i) anti-corrosion, (ii) repair and (iii)
resurfacing mortar or cement compositions apply mutadis mutandis to the reduction
to practice of the afore-mentioned use for the respective uses (i), (ii) and (iii),
respectively.
[0066] In yet another aspect, there is provided a method for repairing a damaged reinforced
concrete structure, comprising steps of:
- (i) applying an anti-corrosion mortar or cement composition according to any one of
the preceding embodiments to exposed steel pieces of the damaged reinforced concrete
structure;
- (ii) applying a repair mortar or cement composition according to any one of the preceding
embodiments to the reinforced concrete structure obtained in step (i) to repair, fill
and/or spray damages, cracks, flaws and cavities present in the structure, and
- (iii) smoothing the surface of the repaired concrete structure obtained in step (ii)
by applying a resurfacing mortar or cement composition according to any one of the
preceding embodiments to the surface.
[0067] As the reader will readily appreciate, the method described directly above represents
a complete and optimal variant of the three different uses associated with the multi-purpose
cement or mortar composition according to the invention (i.e., anti-corrosion, repair
and resurfacing applications/uses, respectively). Using the same basic (multi-purpose)
cement/mortar composition for all three applications/uses allows a good, if not better,
chemical compatibility between the different layers (i.e., anti-corrosion, repair
and resurfacing layers) than if a different composition was used for one or two of
the applications/uses.
[0068] After each step (i), (ii) and/or (iii), the anti-corrosion, repair and resurfacing
mortar or cement composition may be allowed to set prior to applying the composition
of the next step, or any other product. Again, the various embodiments described herein
for the (i) anti-corrosion, (ii) repair and (iii) resurfacing mortar or cement compositions
apply mutadis mutandis to the reduction to practice of the afore-mentioned method
for repairing a damaged reinforced concrete structure, in particular in effecting
the different steps (i), (ii) and (iii), respectively.
[0069] Accordingly, the present invention provides a single multi-purpose mortar or cement
composition which can be used as a concrete repair system, an anti-corrosion system
and/or a concrete surfacing system, merely by adjusting the water content added to
the mortar composition. In other words, a single product can be used to carry out
three different steps of conventional concrete reparation.
[0070] It is the first product of its kind meeting all three European Standards EN 1504-2,
EN 1504-3 and EN 1504-7.
[0071] Adjusting the water ratio produces three different consistencies which correspond
to the application type. In short, there are three different products contained into
one bag.
[0072] It is easy to mix, easy to apply and very easy to smooth and finish. It also takes
up little space and stores for a long time.
[0073] The present invention therefore offers the advantages of reduced packaging in size
and in amount (since three products are packages into one), and thus fewer waste materials.
It is thus more cost efficient, and environmentally friendly than existing products.
[0074] Other features and advantages will be apparent to the skilled person in the art upon
reading the description and Examples below, which are provided for illustrative purposes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0075]
Figure 1 represents a photograph of a metallic plate coated with an anti-corrosion
mortar according to Example 1 after immersion for 7 months in water.
The picture shows that there is no corrosion propagation.
Figure 2 represents a photograph of a metallic plate not coated with an anti-corrosion mortar according to the invention, after immersion
for 7 months in water. The picture shows that there is strong propagation of corrosion
on the plate.
Figure 3 represents a schematic view of the assembly used in a shear adhesion test
of coated steel bars to concrete, as described in the corrosion protection test of
Example 5.
Figure 4 represents a photo of an actual specimen used to conduct the corrosion protection
test described in Example 5. The photo shows a plate in the centre, and four bars
of different diameters, all coated with a test mortar.
Figures 5A and 5B represent two side views of the specimen of figure 4, after the
different storage stages described in EN 15183.
[0076] The pictures of Figures 4, 5A and 5B are presented for illustrative purposes only:
the mortar coating the specimens is not a mortar or cement composition according to
the present invention.
[0077] Figure 6 pictures an example of mixer that may be used to mix with water the multi-purpose
mortar or cement compositions according to the invention to prepare (i) repair, (ii)
anti-corrosion, or (iii) resurfacing mortar or cement compositions according to the
present invention.
[0078] Figures 7A through 7H depict the various stages of the Baenziger block test described
in Example 6.
[0079] Figure 8 depicts the revelation of cracks by spraying a mortar surface with water
to enhance crack lines in a Baenziger test according to Example 6. In the picture,
the mortar is not a mortar or cement composition according to the present invention.
[0080] Figure 9 depicts a table summarizing additional test methods to be used in the Baenziger
if the mortar has not cracked within the defined period.
[0081] Figure 10 depicts typical results after assessment of mortar quality under the Baenziger
test (Example 6). In the pictures, the mortar is not a mortar or cement composition
according to the present invention.
[0082] Figure 11 depicts an exemplary Baenziger block specification.
[0083] Figures 12A and 12B depict examples of mortars that perform poorly under the Baenziger
test (Example 6). In the pictures, the mortar is not a mortar or cement composition
according to the present invention.
[0084] Figures 13A through 13D depict examples of test results under the Baenziger test
(Example 6) of the repair mortar or cement composition of Example 3 according to the
present invention. As evidenced in the pictures, the test revealed not cracks and
to shrinkage problems.
[0085] Figures 14A and 14B depict schematic views of Baenziger blocks of a repair mortar
or cement composition of Example 3 in the measurement of bond stress by pull-off as
described in Example 7, at full thickness and half-thickness, respectively. Each drawing
indicates the bond strength measured at each indicated point of the Baenziger block.
[0086] Figure 15 is a photo of a Baenziger block of a repair mortar or cement composition
according to the present invention that was subjected to the measurement of bond stress
by pull-off as described in Example 7. The tested mortar or cement composition was
prepared according to Example 1, except that 0.500% by weight of Sika ASA 40(anti-shrinkage
agent, SIKA) was used instead of Dispelair P 430 (% by weight, calculated on the total
weight of the composition).
EQUIVALENTS
[0087] The representative examples that follow are intended to help illustrate the invention,
and are not intended to, nor should they be construed to, limit the scope of the invention.
Indeed, various modifications of the invention and many further embodiments thereof,
in addition to those shown and described herein, will become apparent to those skilled
in the art from the full contents of this document, including the examples which follow
and the references to the scientific and patent literature cited herein. It should
further be appreciated that the contents of those cited references are incorporated
herein by reference to help illustrate the state of the art.
[0088] The following examples contain important additional information, exemplification
and guidance that can be adapted to the practice of this invention in its various
embodiments and the equivalents thereof.
EXAMPLES
[0089] The compositions of this invention and their preparation can be understood further
by the examples that illustrate some of the processes by which these compositions
are prepared or used. It will be appreciated, however, that these examples do not
limit the invention. Variations of the invention, now known or further developed,
are considered to fall within the scope of the present invention as described herein
and as hereinafter claimed.
Example 1. Multi-purpose mortar or cement composition
[0090] The following starting materials are mixed and blended to form 25 kg of a multi-purpose
mortar or cement composition according to the invention:
- 25.755% of cement CPA CEM I 42.5 R (from Gaurain)(CIMENTS CALCIA / ITALCEMENTI GROUP)
- 7.790% of calcareous filler BEMAP® N°12 (bulk) (SOCIETE DES CABRONATES PIKETTI)
- 21.500% of SB sand (bulk)(FULCHIRON)
- 21.500% of NE 34® sand (bulk)(SIBELCO)
- 16.000% Of TH 158® sand (bulk)(SABLIERES DE THIEULIN)
- 0.100% of Rhoximat DF 6352 DD® (MOMENTIVE)
- 0.050% of Sikament FF 86® powder (30 kg) (SIKA)
- 1.000% of Socal 31® (UNIVAR)
- 0.020% of chromatex C ® (TRICOSAL CHEMIE)
- 0.950% of sodium nitrite (bag)(BRENNTAG)
- 0.200% of fibre XL 325 (CALDIC BELGIUM)
- 1.500% of calcium formate (EK)(AMIK)
- 0.500% of Expan-K (MITSUI&CO)
- 0.035% of Unifoam AZ ultra 1050 (box)(BRENNTAG)
- 0.100% of tris(hydroxymethyl)aminomethane (bag) (JOHNSON
MATTHEY)
[0092] The product is in the form of a grey powder, and has a storage shelf-life of 12 months
from production if stored properly in undamaged original sealed packaging in dry cooled
conditions.
Example 2. Anti-corrosion mortar or cement composition
[0093] 4.6 to 5.1 liters of water were placed into a suitable mixing container. While stirring,
25 kg of the multi-purpose mortar or cement composition prepared in Example 1 was
slowly added into the water. The resulting mixture was stirred homogeneously at slow
speed (∼500 rpm) for at least 3 minutes using a mixer with single or double mixing
paddle, such as that shown in Figure 6, to form a mortar or cement having the consistency
of a paint.
[0094] The resulting anti-corrosion mortar had a pot-life of about 30 minutes.
[0095] A first layer of the resulting anti-corrosion mortar was applied lightly using a
clean brush around the whole exposed circumference of the steel reinforcement of a
damaged concrete structure, by dabbing or lightly touching the mortar composition
onto the steel to form a thin layer. Care was taken not to over-brush on the surface
so as to not wipe away the mortar.
[0096] After the first layer has dried (approximately 1 hour at 21 °C, as tested by the
fingernail method on the surface), any loose material was wiped away. The first layer
was then pre-wet. Excess water was removed, and a second layer of the mortar composition
was applied until the total application thickness was ≥ 2 mm.
[0097] For best results, two brushes may be used to ensure coverage of the steel bar circumference.
Requirements according to EN 1504-7 (mixing ratio 19% as corrosion protection) |
|
Test Method |
Requirement |
Corrosion protection |
EN 15183 |
Coated zones of steel free of corrosion and rust creep at the ground plate edge <
1 mm |
Shear adhesion (coated steel to concrete) |
EN 15184 |
Bond stress with coated bars is at least 80% of reference bond stress for un-coated
bars |
Example 3. Repair mortar or cement composition
[0098] 3.4 to 4.0 liters of water were placed into a suitable mixing container. While stirring,
25 kg of the multi-purpose mortar or cement composition prepared in Example 1 was
slowly added into the water. The resulting mixture was stirred homogeneously at slow
speed (∼500 rpm) for at least 3 minutes using a hand-mixer machine with single or
double mixing paddle to form a mortar or cement having a thick consistency.
[0099] The resulting repair mortar had a pot-life of about 60 minutes.
[0100] The resulting repair mortar was pressed firmly on the repair area, while ensuring
that all the substrate pores and pits were filled, using traditional trowel techniques
or a suitable machine application (wet spray method).
[0101] If the repair depth exceeds the maximum layer thickness, the repair mortar may be
built up in layers. In that case, the first layer should be allowed to dry before
applying subsequent layers.
[0102] The repair mortar was applied on the damaged concrete structure treated in Example
2.
Mechanical/physical properties (20°C in laboratory conditions) |
|
1 day |
7 days |
28 days |
Compressive strength |
∼5 N/mm2 (MPa) |
∼22 N/mm2 (MPa) |
∼30 N/mm2 (MPa) |
Flexural strength |
∼1 N/mm2 (MPa) |
∼4 N/mm2 (MPa) |
∼7 N/mm2 (MPa) |
Shrinkage |
∼600 µm/m @ 21 °C 65% RH at 28 days and
15%water:powder ratio (EN 12617-4) |
Requirements according to EN 1504-3 (mixing ratio 15% as repair mortar) |
|
Test Method |
Requirement (R2) |
Compressive strength |
EN 12190 |
≥ 15 N/mm2 (MPa) |
Chloride ion content |
EN 1015-17 |
≤ 0.05% |
Adhesive bond |
EN 1542 |
≥ 0.8 N/mm2 (MPa) |
Restrained shrinkage/expansion |
EN 12617-4 |
≥ 0.8 N/mm2 (MPa) |
Carbonation resistance |
EN 13295 |
Passes (no requirement) |
Elastic modulus |
EN 13412 |
Declared value (no requirement) |
Thermal compatibility Part 1: Freeze-thaw |
EN 13687-2 |
≥ 0.8 N/mm2 (MPa) |
Thermal compatibility Part 4: Freeze-thaw |
EN 13687-2 |
≥ 0.8 N/mm2 (MPa)≥ |
Capillary absorption |
EN 13057 |
≤ 0.5 kg.m-2.h-0.5 |
Example 4. Resurfacing mortar or cement composition
[0103] 4.1 to 4.6 liters of water were placed into a suitable mixing container. While stirring,
25 kg of the multi-purpose mortar or cement composition prepared in Example 1 was
slowly added into the water. The resulting mixture was stirred homogeneously at slow
speed (∼500 rpm) for at least 3 minutes using a hand-mixer machine with single or
double mixing paddle to form a mortar or cement having a consistency intermediate
between the compositions obtained in Examples 2 and 3.
[0104] The resulting resurfacing mortar had a pot-life of about 40 minutes.
[0105] The resulting resurfacing mortar was applied to a concrete surface by conventional
methods.
[0106] When applied in layers, the surface of the first layer was first rougher prior to
application of the subsequent layer.
[0107] When the first layer has hardened, any laitance layer was removed and pre-wet prior
to applying the second layer. For best results, the first layer should be allowed
to dry before applying the subsequent layers.
Requirements according to EN 1504-2 (mixing ratio 17% as resurfacing coating) |
|
Test Method |
Requirement |
Compressive strength |
EN 12190 |
No requirement |
Permeability to water vapour |
ISO 7783-2 |
Class I Sd ≤ 5 m |
Capillary absorption and permeability to water vapour |
EN 1062-3 |
≤ 0.10 kg.m-2.h-0.5 |
Permeability to CO2 |
EN 1062-6 |
Sd > 50 m |
Adhesion pull off |
EN 1542 |
≥ 1.0 N/mm2 (MPa) |
Example 5. Corrosion protection test
1- Corrosion protection test. EN 15183:2007
Protocol
[0108]
- A plate and four bars of steel were prepared for the test.
[0109] Following the manufacturer instructions (two layers, total thickness 6 mm - 6 kg/m2
per layer) the product according to Example 2 was prepared and was applied, covering
completely the plate and the steel bars, being left to recover.
- After the product was allowed to harden (7 days), it was placed in the cylindrical
mold, and then it was covered up with concrete just to the half of the height of the
bars and plate.
- The sample was subjected to the corrosion test under the conditions contemplated in
paragraph 6.2 of standard EN 15183:2007, and understanding the following consecutive
stages:
- Stage 1: 10 cycles according EN ISO 6270-2:2006
- Stage 2: 10 cycles according EN ISO 6988:1996
- Stage 3: 120 hours according EN 60068-2-11:2000
- Once the test was finished, the process for assessing the condition of the elements
"Plate" and "Bar" was carried out according to the requirements contemplated in the
paragraph 5.2 of the standard 1504-7:2007, as follows:
- 1- Visual inspection of the sample once extracted from the chamber test.
- 2- Proceed to remove the concrete for visual inspection of the elements "Plate" and
"Bars" in the corresponding zones that were submerged in it.
- 3- Finally, eliminate (by mechanical procedures) the covering of those zones of the
element "Plate" that were covered (and also were initially submerged in the concrete)
to determinate the progression of the underlying corrosion.
TEST CONDITIONS:
- Ist stage: 10 cycles according EN ISO 6270-2:
[0110]
- Machine: DYCOMETAL, model VCK-300
- Sample position: Horizontal
- Every cycle consists: 8 hours at 40°C ± 3°C with closed chamber and 16 hours at 21°C
± 2°C with open chamber and relative humidity 75%.
[0111] The sample was cleaned by wash with water and dried by compressed air.
- 2nd stage: 10 cycles according EN ISO 6988:
[0112]
- Machine: DYCOMETAL, model VCK-300
- Sulphur dioxide: Addition of 0.2 liters for cycle
- Sample position: Horizontal
- Each cycle consists: 8 hours at 40°C ± 3°C in an environment of SO2 with a relative
humidity of 100 % and 16 hours of cooling up to a temperature set of 23°C ± 3.0°C
and a relative humidity of the air of 50 % ± 5 %.
[0113] The cleaning of the sample has been effected by wash with and dried by compressed
air.
- 3rd stage: EN 60068-2-11
[0114]
- Machine: DYCOMETAL, model SSCK1000
- Densimeter: LUDWIG SCHNEIDER, model L 50
- Temperature: 35.0°C ± 1.0°C
- Saline prepared solution:
- Water conductivity: 2.870 µS/cm
- Concentration saline solution: NaCl 5% (p/v)
- pH: 6.6
- Density: 1.032 g/cm3
- Collected solution:
- pH: 6.5
- Volume: 1.2 cm3/hour 80 cm2, and 1.8 cm3/hour 80 cm2.
- Sample position: Horizontal
- Maximum time of exhibition to the saline environment: 120 hours The sample was cleaned
by wash with and dried by compressed air.
RESULTS:
[0115] Once the corrosion test was finished, and the sample was extracted from the interior
of the chamber (after having carried out three consecutive stages, according to the
conditions indicated in paragraph 6.2 of standard 15183:2007) the following observations
can be made:
- The exposed surfaces present red corrosion of a located form, on the lateral edges
of the element "Plate". In the elements "Bars", no trace of rust is detected.
- Once eliminated (by mechanical procedures), the covering zones of the element "Plate"
in which still remaining , start the process to value the condition of them and according
to the requirements contemplated in paragraph 5.2 of standard EN 1504-7:2007. The
results are reflected in the following table:
ELEMENTS |
FINAL RESULTS
(UNE-EN 1504-7:2007) |
Corrosion (1) |
Result (2) |
"Bars" |
Ø 8 mm |
Corrosion is not observed |
PASS |
Ø 16 mm |
Corrosion is not observed |
PASS |
"Plate" |
Corrosion is not observed |
PASS |
NOTES: (1): The standard EN 1504-7:2007, establishes that the progression from the edge zones
in the element "Plate" must not overcome the distance of 1 mm. While for the elements
"Bar" the mentioned specification does not determine any requirement.
(2): In case of the elements "Bar", the valuation is carried out exclusively on the basis
of the aspect of those covered zones that were absorbed in the concrete. Whereas for
the elements "Plate", the progression of the corrosion from its edge zones also has
to be considered, and once has been extracted the covering of the corresponding zones
that also were absorbed in the concrete. |
2- Shear adhesion of coated steel to concrete . EN 15184:2008
[0116] We tested three coated bars and three uncoated bars (reference bars).
[0117] The adhesion length of the bar was 5 times the diameter of the bar (80 mm), with
the rest of the bar covered by a plastic tube leaving the extremity free. Following
the manufacturer instructions (two layers, total thickness 6 mm - 6 kg/m
2 per layer) the product according to example 2 was prepared, and was applied.
[0118] The reference slabs are specimens of 200 x 200 x 200 mm made with aggregates with
a maximum size between 16 and 20 mm with reference concrete type C (0.70) according
to EN 1766:2000.
[0119] After 72 hours of curing time covered with a wet cloth, they are removed from its
mould. Finally, they were preserved at 21 °C and 60% H.R during 25 days,
RESULTS:
[0120]
UNCOATED SPECIMENT |
COATED SPECIMEN |
Specimen n° |
Bond stress at a displacement of 0.1 mm (kN) |
Type of failure |
Specimen n° |
Bond stress at a displacement of 0.1 mm (kN) |
Type of failure |
1 |
5.45 |
Type 2 |
1 |
4.95 |
Type 2 |
2 |
5.80 |
Type 2 |
2 |
4.76 |
Type 2 |
3 |
5.20 |
Type 2 |
3 |
4.69 |
Type 2 |
Average |
5.48 |
Average |
4.80 |
Bond stress of coated specimen is 87.6% of the reference bond stress (uncoated specimen) |
[0121] Type of failure:
Type 1: Extraction of the bar from the sealing product.
Type 2: Extraction of the reinforcement bar and sealing product from concrete.
Type 3: Breakage in the sealing product itself.
[0122] According to EN 1504-7:2007, the test is considered to have been passed if the bond
stress determined with the coated bars is in each case at least 80 % of the reference
bond stress determined for the uncoated bars.
Example 6. Baenziger block test
[0123] The purpose of this test is to assess the crack behaviour characteristics of mortars
during development or testing (e.g. competitor products). The special design of this
Baenziger Block allows evaluation of long term performance and susceptibility of the
material to crack under real-life conditions.
[0124] For example, the Baenziger block test may be used to test the repair mortar or cement
compositions of the present invention.
1. The Baenziger Block
1.1 Introduction
[0125] Early failure of mortars can be a result of a wide range of physicochemical processes.
Cracking often occurs when excessive tensile stresses and strains exceed the resistance
capability of the material. These forces are often caused by drying shrinkage and
occur in early stages of curing. When interaction stresses and strains between the
material and substrate are great enough, de-lamination can occur.
[0126] The Baenziger Block has been specifically designed to generate these stresses and
strains at precise locations in order to allow the mortars to crack if they are not
well formulated. This document is a step by step procedure of how to prepare, test,
observe and interpret results using the Baenziger Block.
1.2 Theory
[0127] The Baenziger Block has practical relevance by replicating common stresses and strain
conditions and incorporating them at specific locations. These are:
- 1) Solid concrete substrate so no deformation due to mortar shrinkage is possible.
- 2) Sand blasted substrate to replicate an adequate prepared substrate.
- 3) 90 degree square arises as opposed to bevelled edges for worst case scenario.
- 4) Variable repair thickness so there is a higher standard for slump resistance and
crack resistance.
- 5) An indented corner to test the mortar's ability to withstand radial stresses from
all directions.
- 6) Two zones to replicate ability of material to withstand restrained and unrestrained
shrinkage.
1.3 Advantages
[0128] This test helps reduce product development time enabling direct and meaningful comparisons.
It can also be used to compare different products available in a given market. The
advantages are summarised as follows.
- 1) Efficient - Quicker time taken to introduce new product to customers.
- 2) Development - Formulations which do not meet the requirements for practical use do not undergo
further time-consuming tests.
- 3) Size - Fit to the volume of 25kg repair mortar mix
- 4) Testing - allows different types of testing in laboratory.
- 5) Quality Control - Production batches can quickly be checked in a practical way against results from
laboratory development batches.
- 6) Continuous Assessment - When failure occurs, it is easy to establish whether there are quality differences
between production batches.
- 7) Competitors - Direct and relevant comparisons using competitors' products are possible.
1.4 Manufacture information
[0129] The Baenziger Block is a specially designed pre-fabricated test substrate developed
by Heinz Baenziger and Alexander Bleibler. It is used to simulate real-life job situations.
Refer to Figure 11 for dimensions.
Table 1: Baenziger Block Technical Summary
|
Normal concrete |
Material: |
Cement content 300 - 350 kg/m3. |
|
Portland Cement CEM I 42.5 |
Aggregate (gravel): |
0-16 mm to EN 933-1 |
Reinforcement: |
High Yield Ribbed 6 mm diameter bars at 100mm centres |
Surface finish: |
Sand blasted to standard EN 1766 (minimum 2 mm roughness) |
Baenziger Block volume: |
approx. 28 litre |
Weight: |
Unfilled: approx. 60 kg |
Filled: approx. 81 kg |
Special requirements: |
Min 2 months old before used in tests |
2. Sample Preparation
2.1 General remarks:
[0130]
- The Baenziger Block needs to have a minimum age of 2 months.
- The Baenziger Block is designed for mortar applied in a layer thickness of 30 - 60
mm. If a specific testing material is used in lower layer thickness (see PDS), apply
only the allowed maximum thickness.
- Test is to be carried out in the laboratory with stable conditions (ideally 21°C,
60% relative humidity), similar to EN 1504-3 conditions.
- The test block has to be cleaned and shall be free from dust, loose material, surface
contamination and materials which reduce bond or prevent suction or wetting by repair
materials.
- Use onlv full packaging units (pails, bags) for mixing to get a homogeneous mixture
of the mortar.
- Measure density and air content of each mortar mixture for quality control.
- Application is normally horizontal, but may also be vertical if necessary.
2.2 Application
[0131]
- Pre-damp the block substrate prior to application. (Figures 7A and 7B)
- To be carried out approximately 24 hours before application of the mortar.
- Apply water to all surfaces in contact with mortar including top surface.
- Excess water is to be poured off the substrate surfaces.
- Aim of wetting is to reach a good water saturation to prevent capillary absorption
of the mixed mortar on the substrate.
- Avoid water evaporation by covering the block surfaces with plastic sheet after wetting.
[0132] Before clamping into position, apply mould release agent on iron formwork (wood or
plastic also allowable). Do not paint iron formwork after clamping as some mould release
agent may spill on to Baenziger Block. Use appropriate mould release agent according
to the type of formwork. (Figure 7C) Before applying repair mortar (or bonding primer,
if necessary) remove excess water by drying surface with a towel or sponge. The surface
shall be sufficiently damp without being wet. The surface shall achieve a dark matt
appearance without glistening (no free water on the surface). (Figure 7D) After clamping
iron formwork in position apply mortar directly to substrate (wet on wet to bonding
primer where necessary). (Figure 7E)
Apply mortar by firmly pressing first into corners and walls of block using trowel
(to build strong interface), followed by filling the volume in one layer. (Figure
7F)
Level the mortar surface scrapping off any excess using ruler. If the mortar is also
to be used as smoothing mortar: gently finish surface using rectangular trowel. Otherwise
no post treatment of mortar is necessary.
Do not cover. (Figure 7G)
Store Baenziger Block in laboratory at 21 °C /60% relative humidity. If different
products are to be compared directly with one another, the samples must be mixed at
the same time or very shortly after one another. Remove the formwork 1 hour after
setting time. Refer to the Product Data Sheet for setting time or determine setting
time in accordance with EN 196-3. (Figure 7H)
3. Test Procedures
3.1 Cracks and Delaminations
[0133] To enhance appearance of cracks spray surface lightly with water.
Wait a few minutes for the water on the surface to evaporate in order to reveal established
cracking. Mark visible cracks with different coloured pens. Use different colour pens
for different days to show stages of cracking. Appearance of cracks must be checked
daily during the first week, thereafter weekly. Cracks normally appear within 2 months.
(Figure 8)
[0134] Repair mortar is to be checked daily for sounds of de-lamination by rubbing surface
with metallic object (hammer test). Mark de-lamination zones with a pen.
Table 2: Summary of observation criteria
Observation |
Model Result |
Surface Characterisitcs |
▪ Lattance / glossy finish (Poor adhesion for subsequent filers or coatings |
▪ Smooth homogeneous |
Surface discolouration |
▪ No discolouration |
Cracks along arises (fig 1) |
|
after the start of setting |
▪ Early shrinkage: Objective-no cracks |
after 24 atEr 24 hours |
▪ Early shrinkage: Objective-no cracks |
after n days |
▪ Late shrinkage: Objective-no cracks |
Cracks of the mortar transverse and longitidinal to the member |
▪ Cracks due to shrinkage: Objective no cracks |
Random "Cobweb" cracking (fig 4) |
▪ Water retention capacity: Objective-no cracks |
➢ Sensitivity to drying |
3.3 Additional Assessments
[0135] If the repair mortar has not cracked within the defined period, additional tests
can be carried out (not mandatory), as described in Figure 9.
4.4 Method of Measuring Crack Depth
[0136] This method can be used to measure the depths of very fine cracks.
A water based epoxy resin mixed with a pigment can be used. For example, epoxy resin
Sikafloor-156 components A + B (1:1) may be mixed with 0.8%.weight of floorpaste-3
red, SAP code 2771 as pigment.
Immediately after mixing apply firmly the liquid resin onto top surface of mortar.
Press down on resin just after application to ensure cracks are filled.
Leave resin to dry for minimum 24 hours.
Carefully bore a core sample from the mortar at the crack location and cut sample
to reveal crack depths.
Exemplary results and interpretation guidelines are given in Figure 10.
[0137] Results obtained for the repair mortar or cement composition of Example 3 are provided
in Figures 13A through 13D.
Example 7. Measurement of bond stress by pull-off
[0138] The mortar/cement block obtained in Example 6 was core drilled ("carotté" in French)
at several selected test locations randomly spread over the surface of the mortar/cement
block, to get a representative measurement (cf. figures 14 and 15). Core drilling
was carried out using a diamond coring barrel (WEKA) ("carottier diamanté" in French)
according to a 90 ± 1° relative to the surface. The mortar/cement block was core-drilled
through half the block thickness (Figure 14A) or the full block thickness (Figure
14B).
A dolly ("pastille" in French) was adhesively bonded to each cored surface ("surface
des carottes" in French) after carefully cleaning the surface of each dolly and core
("carotte" in French). The bond stress by pull-off was measured for each core("carotte"
in French) using a Sattec dynamometer.
[0139] The results obtained for the repair mortar/cement composition of Example 3 are given
in Figures 14A (full thickness) and 14B (half thickness). No cracks or delamination
is observed in all cases.
Example 8. Comparative example/corrosion protection
[0140] A test metallic plate was coated with anti-corrosion mortar prepared according to
Example 1. Only one lateral edge ("tranche" in French) is free of material (accessible
to corrosion). The specimen was immerged in a 5% NaCl solution at 35°C (Fig. 1).
[0141] A control virgin metallic plate (i.e., not coated with an anti-corrosion mortar according
to the present invention) was subjected to the same immersion treatment (Fig. 2).
After immersion:
- the free lateral edge ("tranche" in French) of each plate was visually inspected,
and
- the mortar was removed from the first plate and the corrosion propagation was comparatively
evaluated for each plate.
[0142] The comparative results show that the anti-corrosion mortar significantly prevented
corrosion of the test plate.
[0143] While we have described a number of embodiments of this invention, it is apparent
that the basic examples may be altered to provide other embodiments that utilize the
compositions and methods of this invention. Therefore, it will be appreciated that
the scope of this invention is to be defined by the appended claims rather than by
the specific embodiments that have been represented by way of example.
1. A multi-purpose mortar or cement composition for (i) inhibiting the corrosion of steel
in mortar or cement structures, (ii) repairing, filling and/or spraying damages, cracks,
flaws and cavities in mortar or cement structures and (iii) surfacing, coating and/or
protecting mortar or concrete surfaces comprising at least one cementitious binder,
at least one filler and sands.
2. A multi-purpose mortar or cement composition according to claim 1 comprising at least
one fibre component.
3. A multi-purpose mortar or cement composition according to claim 1 or 2 comprising
at least one polymer, redispersable polymer or co-polymer.
4. A multi-purpose mortar or cement composition according to at least one of claims 1
- 3 comprising:
at least one fibre component
at least one anti-corrosion agent
at least one polymer, redispersable polymer or co-polymer.
5. A multi-purpose mortar or cement composition according to at least one of claims 1
- 4 comprising (% by weight, calculated on the total weight of the composition):
15 to 40 % of the at least one cementitious binder
50 to 80 % of the at least one filler and sands
0.05 to 1.2 % of at least one fibre component
0.05 to 3.2 % of at least one anti-corrosion agent
0.1 to 3.5 % of at least one polymer, redispersable polymer or co-polymer;
wherein the sum of the weight % of the aforementioned components is 100%.
6. A multi-purpose mortar or cement composition according to at least one of claims 1
- 5 comprising:
at least one antifoam agent
at least one fibre component
at least one anti-corrosion agent
at least one plasticizer or superplasticizer
at least one accelerator
at least one anti-shrinkage agent
and at least one polymer, redispersable polymer or co-polymer.
7. A multi-purpose mortar or cement composition according to at least one of claims 1
- 6 comprising:
15 to 40 % of at least one cementitious binder
50 to 80 % of at least one filler and sands
0.05 to 1.5 % of at least one antifoam agent
0.05 to 1.2 % of at least one fibre component
0.05 to 3.2 % of at least one anti-corrosion agent
0.05 to 1.2 % of at least one plasticizer or superplasticizer
0.1 to 3.5 % of at least one accelerator
0.1 to 4.2 % of at least one anti-shrinkage agent
0.1 to 3.5 % of at least one polymer, redispersable polymer or co-polymer,
in particular selected from polyvinyl acetate or polyvinyl ester, or a mixture thereof;
wherein the sum of the weight % of the aforementioned components is 100%.
8. A multi-purpose mortar or cement composition according to at least one of claims 1
- 7, wherein the cementitious binder is a Portland cement, a calcium aluminate cement
(CAC), a sulfo aluminate cement, a gypsum-based binder, lime, hydrated lime, silica
fume, or a mixture thereof.
9. A multi-purpose mortar or cement composition according to at least one of claims 1
- 8, wherein the filler or sands are siliceous sands or filler having a sieve curve
between 0.05mm and 1.5mm, calcareous filler, precipitated ultra fine calcium carbonate,
or a mixture thereof.
10. A multi-purpose mortar or cement composition according to at least one of claims 1
- 9, wherein the fibre component is polyolefines fibres, nitryl, polyvinyl alcohol
(PVA), glass with or without anti-alkaline protection, cellulose, flax or hemp fibre
component, or a mixture thereof.
11. A multi-purpose mortar or cement composition according to at least one of claims 1
- 10, wherein the anti-corrosion agent is sodium nitrite, calcium nitrite, dicyclohexylamine
nitrite, mono-ethanolamine benzoate, ethanolamine benzoate, ethanolamine, diethanolamine,
N.N-dimethylethanolamine, TRIS(hydroxymethyl-aminomethan), or a mixture thereof.
12. A wet mortar or cement composition comprising a multi-purpose mortar or cement composition
according to any one of claims 1 - 10 and 13.60 to 20.40 % by weight of water relative
to the weight of the multi-purpose mortar or cement composition.
13. Use of a composition of a multi-purpose mortar or cement composition according to
any one of claims 1 to 11 for (i) inhibiting the corrosion of steel in mortar or cement
structures, (ii) repairing, filling and/or spraying damages, cracks, flaws and cavities
in mortar or cement structures and (iii) surfacing, coating and/or protecting mortar
or concrete surfaces.
14. A method for preparing a composition of a multi-purpose mortar or cement composition
according to any one of claims 1 to 11 by mixing and blending together all of the
components.
15. A method comprising (i) inhibiting the corrosion of steel in mortar or cement structures,
(ii) repairing, filling and/or spraying damages, cracks, flaws and cavities in mortar
or cement structures and (iii) surfacing, coating and/or protecting mortar or concrete
surfaces, by using a composition of a multi-purpose mortar or cement composition according
to any one of claims 1 to 11 or by using a wet mortar or cement composition according
to claim 12.